Bone Marrow Swelling: Spondyloarthritis or Healthy Athlete?

Healthy athletes experience bone marrow edema similar to that experienced in the lower spine of patients with spondyloarthritis of the axial spine.

Using MRI of the sacral spine may help differentiate patients with normal or low-level bone marrow edema from those in need of rheumatologic care and treatment for spondyloarthritis.

Low-grade bone marrow edema in the posterior lower ilium or anterior upper sacrum likely is not sufficient to make a diagnosis of axial spondyloarthritis.

Ulrich Weber and fellow researchers in Denmark pointed out that there is debate as to what a positive sacroiliac joint MRI sequence is in patients with axial spondyloarthritis.

The authors stated, “We lack a data-driven threshold or ‘reference range,’ which reliably discriminates patients with spondyloarthritis from the bone marrow edema ‘background noise’ in healthy individuals, or from bone marrow edema seen in patients with mechanical back pain.”

The authors sought to learn more about the background noise found in sacroiliac joint MRIs of healthy athletes with mechanical strain and presented their findings at ACR/ARHP Annual Meeting in San Diego.

The study
They examined 42 healthy athletes with MRIs of their sacroiliac joints before and after strenuous workouts. Independent, blinded readers read the scans for bone marrow edema.

The results
• On average, healthy runners had bone marrow edema in 3.1 sacroiliac joint quadrants before and after running; hockey players had edema in 3.6 quadrants.

• Edema was found most frequently in the posterior lower ilium, followed by the anterior upper sacrum.

• Both professional and recreational athletes had bone marrow edema in 3 or 4 joint quadrants.

Implications for physicians
• Sacroiliac joint bone marrow edema alone cannot be used to make a diagnosis of spondyloarthritis, especially in young athletic patients.

• A reference range of sacroiliac bone marrow edema in healthy athletes may aid in developing a threshold for suspecting spondyloarthritis.

• The high cost and risk of adverse effects with treatment for spondyloarthritis should lead physicians to be cautious when considering the diagnosis based on MRI findings.

• Low-grade bone marrow edema should be interpreted cautiously, particularly that located in the posterior lower ilium or anterior upper sacrum.

“This study’s results may enhance management of SpA patients by allocating treatment resources more specifically, especially if a rheumatologist is considering effective, but expensive, biological therapy,” Dr Weber stated in a press release.

References:

American College of Rheumatology Press Release. “Young Athletes Commonly Develop Bone Marrow Edema in the Joints of the Lower Spine.” November 4, 2017.

Weber U, Jurik AG, Zejden A, et al. “Bone Marrow Edema in Sacroiliac Joints of Young Athletes Is Common and Shows Most Frequently in the Posterior Lower Ilium.” Abstract Number 1830. 2017 ACR/ARHP Annual Meeting; San Diego, California.